scholarly journals The Tribological Behavior of some Steel Samples Prepared by Powder Metallurgy Sintered in Microwave Field

2015 ◽  
Vol 13 ◽  
pp. 114-117
Author(s):  
Adrian Olei ◽  
Sorin Savu ◽  
Iulian Stefan
Keyword(s):  
Powder Metallurgy ◽  
Microwave Field ◽  
Sintering Temperature ◽  
Wear Behavior ◽  
High Energy ◽  
Wear Testing ◽  
Iron Powders ◽  
Heating Installation ◽  
High Energy Ball Mill ◽  
Energy Ball

The objective of this research is to observe the influence of the sintering temperature on the wear testing for some steel samples elaborated by powder metallurgy technology. For obtaining the steels there were used iron powders and graphite powders. The powders were homogenized in a high energy ball mill Pulverisette 6, cold compacted and then sintered using a Muegge type microwave heating installation. The influence of the sintering technique on the samples’ wear behavior is studied using both a tribometer and a profilometer.

The Influence of the Sintering Temperature on the Wear Testing for Some Steels Samples Obtained by Powder Metallurgy

2014 ◽  
Vol 216 ◽  
pp. 216-221 ◽  
Author(s):  
Bebe Adrian Olei ◽  
Iulian Ştefan ◽  
Nicoleta Popescu
Keyword(s):  
Powder Metallurgy ◽  
Ball Mill ◽  
Sintering Temperature ◽  
Wear Behavior ◽  
High Energy ◽  
Wear Testing ◽  
Iron Powders ◽  
High Energy Ball Mill ◽  
Energy Ball

The objective of this research is to observe the influence of the sintering temperature on the wear testing for some steel samples elaborated by powder metallurgy technology. For obtaining the steels there were used iron powders and graphite powders. The powders were homogenized in a high energy ball mill Pulverisette 6, cold compacted and then sintered in a furnace. The sintering parameters are: the sintering temperature, T = (1050, 1100, 1150)°C and the maintaining time, t = 60 minutes. The influence of the sintering parameters on the samples wear behavior is studied using both a tribometer and a profilometer.

Recycling of Zircaloy Machining Chips by VAR Remelting and Powder Metallurgy Techniques

2012 ◽  
Vol 727-728 ◽  
pp. 356-361 ◽  
Author(s):  
Hidetoshi Takiishi ◽  
J.H. Duvaizen ◽  
I.M. Sato ◽  
J.L. Rossi ◽  
L.A.T. Pereira ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Nuclear Reactor ◽  
Reactor Core ◽  
High Energy ◽  
Powder Metallurgy Method ◽  
High Energy Ball Mill ◽  
Before And After ◽  
Energy Ball ◽  
Near Net Shape ◽  
Small Parts

In the fabrication of nuclear reactor core parts, machining chips of Zircaloy are generated. These alloys are strategic for nuclear technology and cannot be discarded. In the present work are presented two methods for recycling of Zircaloy chips. One of the methods is by melting in VAR furnace and the other by powder metallurgy method. By this method the Zircaloy was submitted to hydriding process and milled in a high-energy ball mill. The powder was cold isostatically pressed and vacuum sintered. The elemental composition of the samples obtained by both ways was determined by XRF and compared to the specifications. The phase composition was determined by XRD. The microstructures resulting of both processing methods, before and after rolling were characterized using optical and scanning electron microscopy. The good results of the powder metallurgy method suggest the possibility of producing small parts, like cladding cap-ends, using near net shape sintering.

scholarly journals Effects of Milling Atmosphere and Increasing Sintering Temperature on the Magnetic Properties of Nanocrystalline Ni0.36Zn0.64Fe2O4

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Abdollah Hajalilou ◽  
Mansor Hashim ◽  
Halimah Mohamed Kamari ◽  
Mohamad Taghi Masoudi
Keyword(s):  
Magnetic Properties ◽  
Sintering Temperature ◽  
Parallel Evolution ◽  
High Energy ◽  
High Energy Ball Mill ◽  
Zn Ferrite ◽  
Crystallite Sizes ◽  
Energy Ball ◽  
Xrd Patterns ◽  
Fesem Micrographs

Nanocrystalline Ni0.36Zn0.64Fe2O4was synthesized by milling a powder mixture of Zn, NiO, and Fe2O3in a high-energy ball mill for 30 h under three different atmospheres of air, argon, and oxygen. After sintering the 30 h milled samples at 500°C, the XRD patterns suggested the formation of a single phase of Ni-Zn ferrite. The XRD results indicated the average crystallite sizes to be 15, 14, and 16 nm, respectively, for the 30 h milled samples in air, argon, and oxygen atmospheres sintered at 500°C. From the FeSEM micrographs, the average grain sizes of the mentioned samples were 83, 75, and 105 nm, respectively, which grew to 284, 243, and 302 nm after sintering to 900°C. A density of all the samples increased while a porosity decreased by elevating sintering temperature. The parallel evolution of changes in magnetic properties, due to microstructural variations with changes in the milling atmosphere and sintering temperature in the rage of 500–900°C with 100°C increments, is also studied in this work.

Sintering of Fe-TiC Composite Prepared by Carbothermal Reduction of Hematite and Anatase

2011 ◽  
Vol 471-472 ◽  
pp. 670-673
Author(s):  
Mohd Salihin Hassin ◽  
Palaniandy Samayamutthirian ◽  
Zuhailawati Hussain
Keyword(s):  
Carbothermal Reduction ◽  
Sintering Temperature ◽  
Milled Powder ◽  
High Energy ◽  
Argon Atmosphere ◽  
X Ray Diffraction ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Cold Pressed ◽  
And Diffusion

In this study, the formation of Fe-TiC composite through carbothermal reduction of hematite and anatase was investigated with various sintering temperature. Mixture of hematite and anatase powders was milled with graphite for 20 hours in a high energy ball mill in argon atmosphere with composition of Fe-30%volTiC. The as-milled powder was analyzed with X-ray diffraction analysis and the result shows broadening of hematite peaks with disappearance of anatase and graphite peaks due to refinement of powder and diffusion of carbon. The as-milled powder was cold pressed under 200 MPa and sintered in argon atmosphere at various sintering temperature i.e, 1200°C, 1300°C and 1400°C. Higher sintering temperature facilitated reduction of hematite and anatase to produce Fe-TiC composite.

scholarly journals Grain Growth Dominance on Complex Permittivity of MgTiO3

2019 ◽  
Vol 7 (2) ◽  
Author(s):  
D. N. F. Abdul Halim ◽  
M. S Abdullah ◽  
J. Hassan ◽  
M. Hashim ◽  
R. S. Aziz ◽  
...  
Keyword(s):  
Grain Growth ◽  
Complex Permittivity ◽  
Sintering Temperature ◽  
Interfacial Polarization ◽  
Dielectric Materials ◽  
High Energy ◽  
X Ray Diffraction ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Diffraction Patterns

Uncovering the relationship between microstructural and dielectric properties is beneficial for designing new dielectric materials for technological purpose. Thus, this work attempts to understand the evolving relationship between complex permittivity and microstructural in magnesium titanate (MgTiO3) at 40 Hz to 1 MHz. Magnesium oxide and titanium dioxide were mechanically crushed using a high energy ball mill for 12 hours via the mechanical alloying method. Pellets were formed followed by a sintering process from 500 oC up to 1400 oC. The phase formations of the sintered samples showed a development in their crystalline structure and their phase was confirmed by X-ray diffraction patterns, yielding a completed phase of MgTiO3 formed at 800 oC. Observation by scanning electron microscopy revealed an improvement in grain growth as the sintering temperatures are elevated. The density proportionally increased with the sintering temperature. From the complex permittivity studies, the dielectric constant, ԑr’ showed a decreasing trend with increasing frequency and attained constant limitation value of ԑr’ at higher frequency at room temperature. Below 104 Hz, the relaxation belonged to the interfacial polarization while beyond 104 Hz, it is dominant by dipolar polarization. The frequency dependence of loss tangent, tan δ decreased with value almost zero at higher frequency for all sintering temperatures. A significant increasing trend was observed which correlated the polarization-crystallinity behaviors at 1 MHz from 500 oC up to 1400 oC. The improvement in microstructure properties with respect to the sintering temperature was observed which give rise to the dielectric permittivity at infinite frequency, ε∞’. It revealed the dependency of dipolar polarization on the grain sizes and the crystallinity of the sample.

scholarly journals Defect-induced B4C electrodes for high energy density supercapacitor devices

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Özge Balcı ◽  
Merve Buldu ◽  
Ameen Uddin Ammar ◽  
Kamil Kiraz ◽  
Mehmet Somer ◽  
...  
Keyword(s):  
Active Carbon ◽  
High Performance ◽  
Carbon Sources ◽  
High Energy ◽  
High Energy Density ◽  
Synthesis Conditions ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
G Ratio ◽  
Energy And Power Density

AbstractBoron carbide powders were synthesized by mechanically activated annealing process using anhydrous boron oxide (B2O3) and varying carbon (C) sources such as graphite and activated carbon: The precursors were mechanically activated for different times in a high energy ball mill and reacted in an induction furnace. According to the Raman analyses of the carbon sources, the I(D)/I(G) ratio increased from ~ 0.25 to ~ 0.99, as the carbon material changed from graphite to active carbon, indicating the highly defected and disordered structure of active carbon. Complementary advanced EPR analysis of defect centers in B4C revealed that the intrinsic defects play a major role in the electrochemical performance of the supercapacitor device once they have an electrode component made of bare B4C. Depending on the starting material and synthesis conditions the conductivity, energy, and power density, as well as capacity, can be controlled hence high-performance supercapacitor devices can be produced.

A Study of Exchange-Coupling Effect on Nd2Fe14B / α-Fe Forming Core/Shell Shape

2007 ◽  
Vol 119 ◽  
pp. 147-150 ◽  
Author(s):  
Chang Woo Kim ◽  
Young Hwan Kim ◽  
Don Keun Lee ◽  
In Chul Jeong ◽  
Hae Woong Kwon ◽  
...  
Keyword(s):  
Exchange Coupling ◽  
Ball Mill ◽  
Coupling Effect ◽  
Chemical Reduction ◽  
High Energy ◽  
Shell Shape ◽  
Core Shell ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Mill Process

We report the core/shell type as the interesting one of the various techniques to prepare exchange-coupled permanent magnet. In this study, the exchange-coupled Nd2Fe14B/α-Fe was prepared by high energy ball mill process and chemical reduction. Nd15Fe77B8 powder prepared by high energy ball mill process was coated with α-Fe nanoparticle by chemical reduction. α-Fe nanoparticle on the ball milled Nd15Fe77B8 was synthesized by chemical reduction with borohydride as a reducing agent in aqueous solution. After annealing, Nd2Fe14B/α-Fe forming core/shell shape has exchange-coupling effect and was identified by using XRD, FE-SEM, VSM, TMA and EDX.

scholarly journals Structure and Deformation Behavior of Ti-SiC Composites Made by Mechanical Alloying and Spark Plasma Sintering

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1276 ◽  
Author(s):  
Dariusz Garbiec ◽  
Volf Leshchynsky ◽  
Alberto Colella ◽  
Paolo Matteazzi ◽  
Piotr Siwak
Keyword(s):  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Indentation Size Effect ◽  
Sintering Temperature ◽  
High Energy ◽  
Indentation Size ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Energy Ball

Combining high energy ball milling and spark plasma sintering is one of the most promising technologies in materials science. The mechanical alloying process enables the production of nanostructured composite powders that can be successfully spark plasma sintered in a very short time, while preserving the nanostructure and enhancing the mechanical properties of the composite. Composites with MAX phases are among the most promising materials. In this study, Ti/SiC composite powder was produced by high energy ball milling and then consolidated by spark plasma sintering. During both processes, Ti3SiC2, TiC and Ti5Si3 phases were formed. Scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction study showed that the phase composition of the spark plasma sintered composites consists mainly of Ti3SiC2 and a mixture of TiC and Ti5Si3 phases which have a different indentation size effect. The influence of the sintering temperature on the Ti-SiC composite structure and properties is defined. The effect of the Ti3SiC2 MAX phase grain growth was found at a sintering temperature of 1400–1450 °C. The indentation size effect at the nanoscale for Ti3SiC2, TiC+Ti5Si3 and SiC-Ti phases is analyzed on the basis of the strain gradient plasticity theory and the equation constants were defined.

On sinterability of nanostructured W produced by high-energy ball milling

2007 ◽  
Vol 22 (5) ◽  
pp. 1200-1206 ◽  
Author(s):  
R. Malewar ◽  
K.S. Kumar ◽  
B.S. Murty ◽  
B. Sarma ◽  
S.K. Pabi
Keyword(s):  
Sintered Density ◽  
Sintering Temperature ◽  
High Energy ◽  
Deformation Bands ◽  
Dramatic Decrease ◽  
Powder Charge ◽  
Grinding Media ◽  
Energy Ball ◽  
High Level ◽  
First Time

The present investigation reports for the first time a dramatic decrease in the sintering temperature of elemental W from the conventional temperature of ≥2500 °C to the modest temperature range of 1700–1790 °C by making the W powder nanostructured through high-energy mechanical milling (MM) prior to sintering. The crystallite size of the initial W powder charge with a particle size of 3–4 μm could be brought down to 8 nm by MM for 5 h in WC grinding media. Further milling resulted in a high level of WC contamination, which apparently was due to work hardening and the grain refinement of W. A sintered density as high as 97.4% was achieved by sintering cold, isostatically pressed nanocrystalline (8 nm) W powder at 1790 °C for 900 min. The microstructure of the sintered rods showed the presence of deformation bands, but no cracks, within a large number of W grains. The mechanical properties, when compared with the hardness and elastic modulus, of the sintered nano-W specimen were somewhat superior to those reported for the conventional sintered W.

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